With all the factors below added together, it should be more than obvious that CFLs a) don’t save as much energy as claimed; b) don’t give the same quality light as incandescent and halogen lamps; c) cannot be used in any light fitting (luminaire); and d) are not as environmentally friendly and safe as previously assumed.
Before dismissing these statements out of hand, please just take the time to read the referenced facts presented below. Then do the math yourself.
1. As shown under Conversion charts, a good quality 11W CFL gives about as much light as a 40W incandescent bulb when real lumen output and expected light loss is taken into consideration.
2. As shown under Power factor, a typical 11W CFL really uses an equivalent of 20 watts of energy when power factor and ballast use are added to the calculation.
3. As shown under Various limitations, when used in the wrong luminaire, at too high or too low temperature etc., output and/or life rate decreases further, though it’s difficult to give an exact number as this may vary so much with circumstances, e.g. 50% less light when used in recessed downlights and 1-89% or a mean of 40% outdoors at minus 10 degrees C. (So, either get the exact right info on which luminaire each CFL is appropriate for, or subtract some more from potential savings.)
4. As shown under Light reduction, poor quality CFLs will also give less light right from the start and/or lose more and sooner, so subtract 15-65% of estimated savings if you got one of those bargain CFLs at an outlet store and find that it doesn’t seem as bright as it should be or last as long as promised.
5. As shown under Heat replacement effect, if you live in a cooler climate zone and use CFLs indoors, the excess heat may or may not, depending on your heating system, lower heating bills but at least make the room warmer. Cut the savings number in half if you’ve got electric radiators with thermostats, less if you have water radiators or heat pump. If you live in a warm zone and use air conditioning, savings increase.
6. As shown under Life cycle assessment, this is not even including the extra energy used for production of CFLs, shipping from the Far East, transportation to recycling facilities, and safe recycling of the mercury. Including these in the calculation, Gad Giladi D.E.S.A., M.F.A. FPLDA, in his calculation makes a rough estimate of a 1.1 or 1.3 total less energy comsumption of the CFL.
Even if we stop after the first 2 points and assume for the sake of simplicity that the rest is not applicable in an ideal case, we still only save half of the roughly 4% (= 2%) of domestic energy used for home lighting, and less if we bring in more of the above factors.
Also, as mentioned under EU energy statistics, only around 50% of lamps in EU homes are still incandescent, so cut the 2 in half again = 1%. (or about 0.25% of total EU energy consumption).
Is it really worth sacrificing both Light quality in our homes, the Health & wellbeing of some groups, plus risking massive a increase in Mercury pollution due to suboptimal recycling rate, when such small savings can easily be achieved by installing light sensors, dimmers, timers, remote controls or intelligent IR-sensor light switches like the Watt-Stopper, turning down heat one or two degrees, using fewer electric appliances, or simply turning lights off when not in use?